Proton Therapy was developed after WWII and has become a standardized radiological treatment applied to different anomalies and especially for treatment of tumors in different locations in the human body. Proton therapy utilizes a beam of charged and accelerated particles—protons. Such proton beam could be delivered to tumors with significantly less dose to normal tissues and organs than conventional radiotherapy.
Proton beams work on the principle of selective cell destruction by exploiting the Bragg energy peak of ion beams which localizes the majority of the energy distribution of an ion beam within a small physical range. The major advantage of proton treatment therefore over conventional radiation treatments is that most of the energy of the proton beam can be directed and deposited in tissue volumes designated by the physicians-in a three-dimensional pattern by locating the Bragg peak within that volume and changing the beam accordingly during treatment. This capability provides greater control and precision and, therefore, superior conformal dose distribution to conventional photon radiotherapy including Intensity Modulated RadioTherapy (IMRT). Radiation therapy with photons requires that conventional x-rays be delivered into the body in doses sufficient to assure that enough ionization events occur to destroy tumor cells but entrance and exit doses to normal tissue are generally higher than the individual dose to the tumor in a given field.
Advances in ultra-compact laser-driven proton acceleration systems as described in U.S. Pat. No. 8,389,954 provide a means for practical use of proton beams. In order to provide a therapeutically viable proton beam, the low energy protons and broad energy spectrum characteristic of the primary beam must be separated and the remaining proton beam tailored in terms of proton energy spread to meet well-defined clinical criteria. In addition the proton beam must be focused to a small spot size suitable for Pencil Beam Scanning (PBS). The beam delivery system is responsible for separating, tailoring and focusing the proton beam. Existing and standard approaches to beam delivery systems fail to address the large spread in proton energies and angular distribution as typical in laser driven acceleration systems. Furthermore, despite their limited performance existing beam delivery systems are too large to be used with the compact laser driven acceleration systems that could reduce the system foot print and save expensive clinical space.